Cells and High Volumes: Forget What You Think You Know

Cellular manufacturing just isn't for the companies that have low-volume production. That's not just theory. It is being proven out in two supplier plants in Indiana each and every day. Here's a look at what they are doing.

If you attend a manufacturing conference or read a book on the subject, you'll quickly discover that flexibility, as manifest in manufacturing cells, is the way to work. If you ask someone (yourself included) who is involved in high-volume production about flexibility and manufacturing cells, the response will likely include the explanation that they are fine for some operations: those that have short runs and small lots sizes.

The conventional wisdom is that big lots mean dedicated machines; small lots (and frequent changeovers) are the domain of manufacturing cells.

What those conference speakers are talking about and proponents of lean manufacturing are writing about is true.

That the conventional wisdom may be, well, conventional but certainly not competitive.

It is very simple. The Freudenberg-NOK plants in question are high-volume manufacturing facilities and the manufacturing infrastructure utilized each and every day, and not just here or there in a special sport or department, but throughout, is based on cellular manufacturing.

Simpler is better. As the Freudenberg-NOK philosophy has it: "Successful companies will attack their processes with a simple, consistent approach."

The basis of what all Freudenberg-NOK employees do is kaizen: Continuous improvement.

The plan is simple: Eliminate waste.

In order to assure consistency—to get away from the flavor-of-the-month approach—is an on-going, full-company initiative called "GROWTTH": Get Rid of Waste Through Team Harmony.

True cellular manufacturing depends on the cooperation and orchestration of all employees. The reason for this is simple: The objective to get rid of waste means thatallof the people involved in the process must work in a synchronized manner. One-piece flow doesn't allow for build-ups of inventory between processes, so people must do each step in the required manner (a manner, it should be noted, that isn't static, but open to improvement).

U-shaped Cells Sometimes Aren't

Byron Burns, GROWTTH facilitator, Lean Manufacturing, Scottsburg Plant II, describes one of the real beauties of a U-shaped cell—beauty in simplicity and in advantage for the operators. There was a process involving three large presses. The presses were placed next to one another so that the operator would process parts though each press, A-B-C. Because multiple parts were produced, it was necessary to work behind the presses after 50 pieces were produced to perform changeovers.

One of the goals of a U-shaped cell is to minimize walk time. The reason for this is simple: When people are walking, chances are it is non-value-added time. And walking distances, hour after hour, day after day, benefits no one (with the possible exception of Dr. Scholl.) The walking distance for the line-up of presses was 47 feet.

Monuments don't stand at the Scottsburg plants if there is any way that they can be moved for the sake of improving the process. (An example of where this is stymied can be found in Plant I, where there are 78 presses built right into the walls of the plant, and so they must simply stay put—for now, one suspects, because these Freudenberg-NOK people are nothing if not innovative. And William A. Huston, GROWTTH manager, Brake Products Lead Center [a.k.a., Plant I], says that all new presses being brought into the plant are modular. Which leads to another thing to know about cellular manufacturing: It facilitates redeployment of resources. Generally, this redeployment is considered in the context of moving equipment within a plant: the demand for one product line fades and it builds for another product being built, so the equipment for the former, because it is flexible, not limited to special products—is applied to the latter. That's how it works in good, lean facilities.

The people at Freudenberg-NOK are really good at this lean, cellular approach, as they've been practicing lean principles since 1992, when the GROWTTH program was kicked off throughout the organization. About those modular presses that are being brought in: Huston remarks, "If another plant needs them, we can have them out in the parking lot in 20 minutes." Some people think in terms of redeployment just within a particular plant. These guys are thinking about moving them across the country if need be.)

Meanwhile, back to the 47 feet of walking distance in Plant II. It was deemed unacceptable. So how could a U-shaped cell be established? One solution would be to take the two presses flanking the middle one, then moving them so that they were parallel to each other and perpendicular to the one in the middle. That would result in a squared U-shape. Simple, but not optimal.

Burns explains that the solution that the team developed—and realize that cellular manufacturing is done better when there is actual, meaningful involvement of the people who do the work: Don't depend on engineers alone, because no matter how much they know, they don't understand what it really means to walk 47 feet, back and forth, all day long—is actually more of an equilateral triangle in plan view.

•One-piece flow•Machines in order of process•Small, inexpensive and dedicated equipment (i.e., single-purpose)•Multi-process handling workers•Movement is easy in standing operations•Production paced to takt time•Pull production•Standard operations defined•Short lead times•High ratio of value-added to non-value-added.

All of which is good. But in a continuous improvement organization, good isn't good enough. So the objective is to make things even better, to transition to what are called "best practice cells." All of the characteristics of a U-shaped cell are retained. But added to them are:

•5S implemented and maintained•Visual controls in place and maintained•Measurement system in place and maintained•Trained operator permanently assigned•Preventive maintenance system in place•Setup times of less than 10 minutes.

And, yes, the Freudenberg-NOK people go beyond even that, to what they call "model manufacturing cells." These cells have all of the characteristics of best practice cells and:

•Indirect support functions incorporated•Kaizen performed every day.

We've all heard people say things like, "Our journey is never done." More often than not, that may be so, but the operations in question aren't going very far. That's decidedly not the case here. (In addition to this plant-level cellular activity, there's a corporate-wide, inter-plant initiative underway that's rationalizing the firm's engineering and manufacturing resources into what are called "lead centers," which can be thought of as cells brought to the scale of entire product lines, but cells that not only build, but actually include design and engineering. But this is a whole other story...)

Don't Make It Hard—Even Though It Isn'tExactlyChild's Play

Burns points out that sometimes it is difficult to visualize what would be most effective in terms of repositioning machinery on the plant floor by looking at layout drawings. One useful alternative is to take a layout drawing and to cut out the machinery. These can then be moved around on a table top to get a sense of what can be accomplished.

But what he has found to be extremely helpful is an idea that he's "borrowed" from another colleague in the company, which is to go to the toy department of a store and picking up a couple of Lego kits. Then instead of having just two-dimensional representations of the equipment, there is a 3D layout, one that's somewhat closer to the real thing. In fact, using the Lego blocks, an entire factory can be built on a table top.

Once again, realize the simplicity of this approach. To be sure, there are software programs that allow 3D renderings of factories. But by using the Lego blocks, a team meeting can be held and people can gather around a table, not be huddled around a workstation screen. It is a whole lot easier and less inhibiting for someone to grab a Lego press and move it from one place to another than to have to deal with the computer simulation.

It all comes back to simplicity and consistency.

Although the conventional wisdom might have it that cellular manufacturing and high volume production don't mix, the Fruedenberg-NOK plants in Scottsburg, IN, indicate that's not the case, as they are making these parts (the big ones are brake booster diaphragms and the others are an assortment of boots, bushings, seals, grommets, etc.) at a combined volume of hundreds of thousands per day and they are doing so in a one-piece-flow, cellular manufacturing mode.

Think Lean

"What if your competitors did (or are doing) what the companies in this book reported and were cutting lead times by 90 percent, cutting defects to a fraction of what they were, increasing productivity by 10 or 15 percent per year without capital investments, and reducing total cost of their product by 10 percent per year? These are all readily achievable with lean. Do you think they would beat you if they were doing this and you were not? On the other hand, what could you do with these tremendous advantages in cost, quality, and delivery if you were becoming lean and your competitors were not?" So asks Jeffrey K. Liker in a book he edits, Becoming Lean: Inside Stories of U.S. Manufacturers (Productivity Press; Portland, OR; 535 pp.; $35).

Although there is more to lean than manufacturing cells, they are an important element.

Included in the book are a number of notable pieces that provide an up-close look at lean from some of the people who are intimately involved in bringing their organizations to this healthy, agile condition. Among them are an examination of lean at Freudenberg-NOK from the perspective of Joseph C. Day, the firm's CEO. Extremely interesting and useful stories include "Transforming a Plant to Lean in a large, Traditional Company: Delphi Saginaw Steering Systems, GM" by Daniel Woolson and Mike A. Husar—two people who were in the thick of it—and "The Donnelly Production System: Lean at Grand Haven" by Liker and Keith Allman, the general manager for Donnelly Corp.'s Exterior Mirror and Hardware Operations.

All of the pieces included are certainly relevant to anyone who is considering lean—and in light of Liker's questions, who wouldn't consider it?